No one detail is usually enough to make a judgement, you have to consider the whole object and all of the characteristics. Many bases on recent Chinese imports were left unpolished with a rough ground finish. The same is true of much studio glass... As it happens, the finish on many Chinese wares is getting more refined and the general quality may well slowly increase as time goes on.

The main flood of cheap Chinese glass exports seems to have arrived in the last decade but they have been exporting glass for at least the last hundred years (often called Peking glass here), paperweights have been arriving since the 1920s.